Reverse connection prevention circuit for null line and live line

Abstract

The utility model relates to the technical field of anti-reverse-connection circuits, and discloses a null line and live line anti-reverse-connection circuit which comprises a rectifier diode, the positive electrode of the rectifier diode is electrically connected with an AC power supply line L, and the negative electrode of the rectifier diode is electrically connected with one end of a current-limiting resistor R213; the other end of the current-limiting resistor R213 is electrically connected with a pin 1 of a photoelectric coupler, a pin 2 of the photoelectric coupler is electrically connected with one end of a current-limiting resistor R216, and the other end of the current-limiting resistor R216 is electrically connected with an AC power supply PE line; a pin 1 of the photoelectric coupler is electrically connected with a cathode of the voltage stabilizing diode, and an anode of the voltage stabilizing diode is connected with a pin 2 of the photoelectric coupler; a pin 3 of the photoelectric coupler is grounded, a pin 4 of the photoelectric coupler is a TS signal output end and is grounded through a filter capacitor, one end of the TS signal output end is electrically connected with one end of a resistor R215, and the other end of the resistor R215 is connected with a first direct-current power supply; the TS signal output end is electrically connected with the signal input end of the single-chip microcomputer. The device has the advantage of preventing reverse connection of the null line and the live line.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of reverse connection prevention circuit, and in particular to a zero-live line reverse connection prevention circuit. BACKGROUND

[0002] In actual AC application scenarios, zero-live line reverse connection is a problem that cannot be ignored, which often brings many hazards. For example, for commonly used three-hole socket electrical equipment, the electrical switch normally controls the live line. If the zero-live line is reversed, the switch will control the zero line. In this way, even if the switch is turned off, the live line is still in the on state, which makes people easily electrocuted when they accidentally touch the equipment. Moreover, when the line fails, zero-live line reverse connection also causes inconvenience to maintenance work, increases the difficulty and safety risk of maintenance. In addition, for screw caps, if the live line is connected to the screw cap position, the area with electricity is relatively large when powered on, which also has safety hazards. For single P leakage protection, if the zero-live line is reversed, the fixed rule of the connection is broken, and the point corresponding to the N position will always be in the on state. Once the live line is connected, the bottom of the pusher is always live, which has a high risk coefficient.

[0003] The existence of the reverse connection prevention circuit is of great significance to the protection of electrical safety and various electrical equipment. From the perspective of electrical safety, it can effectively prevent electric shock accidents caused by zero-live line reverse connection, protect the personal safety of users, and reduce the occurrence of injuries and deaths caused by improper use of electricity. For electrical equipment, it can prevent the reverse connection of the power supply from damaging sensitive internal components, avoid equipment failure or even scrap, prolong the service life of the equipment, and reduce the use cost.

[0004] The existing reverse connection prevention methods in the prior art include setting a plug to prevent mistakes, but the universality is poor, or distinguishing by marking and color, which has a large human factor. CONTENT OF THE INVENTION

[0005] In order to prevent zero-live line reverse connection and ensure the safety of the circuit, the present application provides a zero-live line reverse connection prevention circuit.

[0006] The zero-live line reverse connection prevention circuit provided by the present application adopts the following technical scheme:

[0007] A zero-live wire anti-reverse connection circuit, comprising a rectifier diode, a positive electrode of the rectifier diode is electrically connected to an AC power supply L line, a negative electrode of the rectifier diode is electrically connected to one end of a current-limiting resistor R213, the other end of the current-limiting resistor R213 is electrically connected to a pin 1 of an optoelectronic coupler, a pin 2 of the optoelectronic coupler is electrically connected to one end of a current-limiting resistor R216, the other end of the current-limiting resistor R216 is electrically connected to an AC power supply PE line; the pin 1 of the optoelectronic coupler is electrically connected to a negative electrode of a voltage stabilizing diode, a positive electrode of the voltage stabilizing diode is electrically connected to the pin 2 of the optoelectronic coupler; a pin 3 of the optoelectronic coupler is grounded, a pin 4 of the optoelectronic coupler is a TS signal output end, the TS signal output end is grounded through a filter capacitor, one end of the TS signal output end is electrically connected to one end of a resistor R215, the other end of the resistor R215 is electrically connected to a first DC power supply; the TS signal output end is electrically connected to a signal input end of a single-chip microcomputer.

[0008] By adopting the above technical scheme, since the zero line is an AC power supply, there is a time interval between high levels after rectification by the rectifier diode; when the power supply is normally connected, the TS output end has a pulse high-low change signal; through sampling and determination by the single-chip microcomputer, it is determined that the connection is normal, and the relay normally outputs power supply to the rear-end circuit; when the connection is reversed, the level is always high and does not change, the single-chip microcomputer determines that the connection is not normal, and thus the relay is controlled not to output, thereby playing a role in protecting the rear-end circuit.

[0009] Optionally, the circuit further comprises a display panel, the display panel is electrically connected to a signal output end of the single-chip microcomputer, and is used for displaying or not displaying a preset pattern according to a signal output by the signal output end of the single-chip microcomputer.

[0010] By adopting the above technical scheme, the circuit normally outputs and works when the connection is normal, and does not output when the connection is reversed; both normal display and abnormal display can be directly read out.

[0011] Optionally, the circuit further comprises a buzzer, the buzzer is electrically connected to another signal output end of the single-chip microcomputer, and is used for alarming according to a signal output by the signal output end of the single-chip microcomputer.

[0012] By adopting the above technical scheme, the alarm is triggered to emit an alarm sound, thereby directly reminding a user that the circuit has a zero-live wire reverse connection problem.

[0013] Optionally, the current-limiting resistor R213 is a variable resistor.

[0014] By adopting the technical scheme, the variable resistor can flexibly adjust the resistance value of the current-limiting resistor according to different circuit loads and application scenarios, so as to adjust the input current of the photoelectric coupler, and ensure that the photoelectric coupler can normally work under different working conditions.

[0015] Optionally, the pin 4 of the photoelectric coupler is also connected to a voltage monitoring circuit of the second DC power supply.

[0016] By adopting the technical scheme, the voltage monitoring circuit can monitor the output signal voltage of the photoelectric coupler in real time, and ensure that the TS signal output is stable and reliable.

[0017] Optionally, the rectifier diode is a fast recovery diode.

[0018] By adopting the technical scheme, the fast recovery diode can be switched from the on state to the off state more quickly, reduce the reverse recovery time, and thus more effectively rectify the alternating current signal, improve the rectification efficiency and accuracy. In the zero fire line anti-reverse connection circuit, the alternating current on the zero line can be more accurately rectified, the accuracy of the TS signal is ensured, and the reliability of the single-chip microcomputer in judging the zero fire line reverse connection is improved.

[0019] Optionally, the negative electrode of the rectifier diode is electrically connected to one end of a filter capacitor, the other end of the filter capacitor is electrically connected to one end of a filter resistor, and the other end of the filter resistor is electrically connected to the PE line of the alternating current power supply.

[0020] By adopting the technical scheme, the filter capacitor and the filter resistor constitute a filter circuit connected between the negative electrode of the rectifier diode and the PE line of the alternating current power supply. The filter circuit can filter the rectified signal, filter out noise and interference signals, and make the signal input to the subsequent circuit more smooth and stable.

[0021] Optionally, a temperature sensor is further included, the temperature sensor is electrically connected to an analog signal input end of the single-chip microcomputer, and the temperature sensor is installed on the circuit board.

[0022] By adopting the technical scheme, the temperature sensor can monitor the temperature of the circuit in real time, and when the temperature exceeds the preset safety range, the single-chip microcomputer can control the corresponding protection mechanism.

[0023] In summary, the present application has at least one of the following beneficial technical effects:

[0024] The core circuit structure composed of rectifier diode, photoelectric coupler, single-chip microcomputer and the like utilizes the level change characteristic of the alternating current on the zero line after rectification, and the sampling and determination by the single-chip microcomputer, so that the normal wiring and reverse connection can be accurately distinguished. When the wiring is normal, the relay normally outputs to supply power to the rear-end circuit, and when the wiring is reversed, the control relay does not output, so as to avoid abnormal work or even damage of the rear-end circuit due to the reverse connection of the zero and fire lines, and the safety of the whole circuit is effectively ensured. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 is a schematic diagram of the reverse connection prevention control unit.

[0026] Figure 2 is a circuit line diagram of the embodiment of the application.

[0027] Figure 3 is a display alarm digital map. DETAILED DESCRIPTION

[0028] The application will be further described below in conjunction with the drawings. It should be understood that the specific embodiments described herein are only used to explain the application, and do not limit the application.

[0029] The embodiment of the application discloses a zero-fire line reverse connection prevention circuit, referring to Figure 1 and Figure 2 , including a rectifier diode D208, the anode of the rectifier diode D208 is electrically connected to the L line of the alternating current source, the cathode of the rectifier diode D208 is electrically connected to one end of a current-limiting resistor R213, the other end of the current-limiting resistor R213 is electrically connected to a pin 1 of a photoelectric coupler U203, a pin 2 of the photoelectric coupler U203 is electrically connected to one end of a current-limiting resistor R216, the other end of the current-limiting resistor R216 is electrically connected to the PE line of the alternating current source; the pin 1 of the photoelectric coupler U203 is electrically connected to the cathode of a voltage stabilizing diode, the anode of the voltage stabilizing diode is electrically connected to the pin 2 of the photoelectric coupler; the pin 3 of the photoelectric coupler U203 is grounded, the pin 4 of the photoelectric coupler U203 is a TS signal output end, the TS signal output end is grounded through a filter capacitor C210, one end of the TS signal output end is electrically connected to one end of a resistor R215, the other end of the resistor R215 is electrically connected to a first direct current source; the TS signal output end is electrically connected to a signal input end of a single-chip microcomputer. In the embodiment, the first direct current source is a +3.3V power supply.

[0030] The zero-live line anti-reverse connection circuit is mainly constructed by rectifier diode, current limiting resistor, photoelectric coupler, voltage stabilizing diode and filter capacitor. The rectifier diode plays a key role in rectification in the circuit, and its anode is connected with the L line of the alternating current power supply, which can preliminarily process the alternating current input and convert it into a unidirectional current form suitable for subsequent circuit analysis. The cathode of the rectifier diode is connected with one end of the current limiting resistor R213, which is used to limit the current size to prevent excessive current from damaging the subsequent elements, and the other end of the current limiting resistor R213 is connected with the pin 1 of the photoelectric coupler. The photoelectric coupler is an important component for realizing electrical isolation and signal transmission, and its pin 2 is connected with one end of the current limiting resistor R216, and the other end of the resistor R216 is connected with the PE line of the alternating current power supply. The voltage stabilizing diode works with the photoelectric coupler, and its cathode is connected with the pin 1 of the photoelectric coupler, and its anode is connected with the pin 2 of the photoelectric coupler, which is used to stabilize the voltage between the input pins of the photoelectric coupler to ensure that the photoelectric coupler can work stably and accurately output signals under different power supply states. The pin 3 of the photoelectric coupler is grounded, and the pin 4 is used as the TS signal output end, which is connected with one end of the resistor R215 through the filter capacitor to filter out the noise interference in the signal, and the other end of the resistor R215 is connected with the first direct current power supply to provide a suitable bias voltage for the subsequent signal processing circuit.

[0031] (I) Normal connection

[0032] When the alternating current power supply is connected to the circuit in the normal zero-live line connection mode, the alternating current will flow into the pin 1 of the photoelectric coupler through the rectifier diode and the current limiting resistor R213 in turn. Due to the periodic change of the alternating current power supply, the voltage between the pin 1 and the pin 2 of the photoelectric coupler also presents periodic change, and when the voltage reaches the turn-on voltage of the light-emitting diode inside the photoelectric coupler, the light-emitting diode emits light, which in turn makes the phototriode inside the photoelectric coupler conductive, at this time, the TS signal output end is grounded and outputs low level; while when the voltage is lower than the turn-on voltage, the light-emitting diode is extinguished, the phototriode is cut off, and the TS signal output end is connected to the first direct current power supply through the resistor R215 and outputs high level. In this way, under the normal connection condition, the TS output end will generate a pulse high-low change signal. If a control unit such as a single-chip microcomputer is connected at the back end, the normal connection state of the power supply can be determined by sampling and judging the pulse signal, and then the relay can be controlled to work normally to provide stable power output for the back-end circuit and ensure the normal operation of the entire system.

[0033] (II) Reverse connection

[0034] If the zero and fire lines of the AC power source are connected in reverse, the current will flow in the opposite direction into the circuit. At this time, due to the unidirectional conductivity of the rectifier diode, the current cannot flow through the rectifier diode in the normal path, but forms a loop through other paths (such as the PE line, etc.). In this way, the voltage between the optocoupler pins 1 and 2 no longer presents a periodic change, but is always in a relatively stable high level state (because the normal AC voltage change is missing to drive the light-emitting diode inside the optocoupler to turn on and off alternately). When the single-chip microcomputer samples the TS signal output terminal, it detects that the level is always high and does not change, and determines that it is an abnormal wiring condition. In this case, the single-chip microcomputer will control the relay to stop outputting, cutting off the connection between the back-end circuit and the power supply, thereby effectively protecting the back-end circuit from damage that may be caused by the zero and fire line connection in reverse, such as the risk of burning out of electrical components, short circuit of the circuit, etc.

[0035] Referring to Figure 3 It also includes a display panel, which in this embodiment is a 3-digit display digital tube; the display digital tube is electrically connected to the signal output terminal of the single-chip microcomputer, and is used to display or not display a preset pattern according to the signal output by the signal output terminal of the single-chip microcomputer. The required normal wiring does not output when the wiring is reversed, and normally outputs and works when the wiring is normal; both abnormal and normal working displays can be read intuitively.

[0036] In other embodiments, a buzzer is also included, which is electrically connected to another signal output terminal of the single-chip microcomputer, and is used to alarm according to the signal output by the signal output terminal of the single-chip microcomputer. When the single-chip microcomputer determines that the wiring is abnormal, in addition to controlling the relay not to output to protect the back-end circuit, it can also trigger the alarm to emit an alarm sound to intuitively remind the user that there is a problem of zero and fire line connection in reverse in the circuit, so that the user can quickly detect abnormal conditions and take appropriate measures in a timely manner, further improving the safety of the circuit in use.

[0037] In other embodiments, the current-limiting resistor R213 is a variable resistor. Using a variable resistor can flexibly adjust the resistance value of the current-limiting resistor according to different circuit loads and application scenarios, thereby adjusting the input current of the optocoupler to ensure that the optocoupler can work normally under different working conditions. The adaptability and adjustability of the circuit are increased, and the compatibility of the circuit in different environments and devices is improved. Users can adjust the resistance value according to actual needs to make the circuit achieve the best working performance.

[0038] In other embodiments, the pin 4 of the optocoupler is also connected to the voltage monitoring circuit of the second DC power supply. Through the voltage monitoring circuit, the output signal voltage of the optocoupler can be monitored in real time, ensuring that the output TS signal is stable and reliable. In different cases of normal wiring and zero fire line reverse connection, the voltage monitoring circuit can provide more accurate basis for the single-chip microcomputer to judge, and when the voltage abnormally fluctuates, it can provide auxiliary information to the single-chip microcomputer for more detailed fault diagnosis and system maintenance, preventing misjudgment caused by unstable signals.

[0039] In other embodiments, the rectifier diode is a fast recovery diode. The fast recovery diode can switch from the on state to the off state more quickly, reducing the reverse recovery time, thereby more effectively rectifying the alternating current signal and improving rectification efficiency and accuracy. In the zero fire line anti-reverse connection circuit, the alternating current on the zero line can be more accurately rectified, ensuring the accuracy of the TS signal, and thereby improving the reliability of the single-chip microcomputer in judging the zero fire line reverse connection.

[0040] In other embodiments, the negative electrode of the rectifier diode is electrically connected to one end of the filter capacitor, the other end of the filter capacitor is electrically connected to one end of the filter resistor, and the other end of the filter resistor is electrically connected to the PE line of the alternating current power supply. The filter capacitor and the filter resistor constitute a filter circuit connected between the negative electrode of the rectifier diode and the PE line of the alternating current power supply. The filter circuit can filter the rectified signal, filtering out noise and interference signals, making the signal input to the subsequent circuit more smooth and stable. At the same time, connecting it to the PE line can better introduce static electricity and electromagnetic interference that may occur into the ground, reducing the influence of interference on the entire circuit, further improving the stability and reliability of the circuit, ensuring that the circuit can work normally in various complex electromagnetic environments, and reducing the possibility of the single-chip microcomputer misjudging the zero fire line reverse connection due to electromagnetic interference.

[0041] In other embodiments, a temperature sensor is also included, which is electrically connected to the analog signal input end of the single-chip microcomputer; the temperature sensor is installed on the circuit board. The temperature sensor can monitor the temperature of the circuit in real time. In normal working state, the single-chip microcomputer can perform temperature monitoring and management according to the feedback signal of the temperature sensor, ensuring that the circuit will not cause safety hazards due to high temperature. When the temperature exceeds the preset safety range, the single-chip microcomputer can control the corresponding protection mechanism.

[0042] The above are preferred embodiments of the present application, which do not limit the protection scope of the present application, therefore: any equivalent changes made according to the structure, shape, principle of the present application shall be covered within the protection scope of the present application.

Claims

1. A zero fire line anti-reverse connection circuit, characterized by, The rectifier diode is electrically connected to the positive pole of the AC power supply L line, the negative pole of the rectifier diode is electrically connected to one end of the current limiting resistor R213, the other end of the current limiting resistor R213 is electrically connected to the pin 1 of the photoelectric coupler, the pin 2 of the photoelectric coupler is electrically connected to one end of the current limiting resistor R216, the other end of the current limiting resistor R216 is electrically connected to the AC power supply PE line; the pin 1 of the photoelectric coupler is electrically connected to the negative pole of the voltage stabilizing diode, the positive pole of the voltage stabilizing diode is electrically connected to the pin 2 of the photoelectric coupler; the pin 3 of the photoelectric coupler is grounded, the pin 4 of the photoelectric coupler is the TS signal output end, the TS signal output end is grounded through the filter capacitor, one end of the TS signal output end is electrically connected to one end of the resistor R215, the other end of the resistor R215 is electrically connected to the first DC power supply; the TS signal output end is electrically connected to the signal input end of the single-chip microcomputer.

2. The zero line anti-reverse connection circuit according to claim 1, characterized in that, It also includes a display panel, which is electrically connected to the signal output end of the single-chip microcomputer, for displaying or not displaying the preset pattern according to the signal output by the signal output end of the single-chip microcomputer.

3. The zero line anti-reverse connection circuit according to claim 2, characterized in that, It also includes a buzzer, which is electrically connected to another signal output end of the single-chip microcomputer, for alarming according to the signal output by the signal output end of the single-chip microcomputer.

4. The zero line anti-reverse connection circuit of claim 1, wherein, The current limiting resistor R213 adopts a variable resistor.

5. The zero line anti-reverse connection circuit of claim 1, wherein, The pin 4 of the photoelectric coupler is also connected to the voltage monitoring circuit of the second DC power supply.

6. The zero line anti-reverse connection circuit of claim 1, wherein, The rectifier diode adopts a fast recovery diode.

7. The zero line anti-reverse connection circuit of claim 1, wherein, The negative pole of the rectifier diode is electrically connected to one end of the filter capacitor, the other end of the filter capacitor is electrically connected to one end of the filter resistor, the other end of the filter resistor is electrically connected to the AC power supply PE line.

8. The zero line anti-reverse connection circuit of claim 1, wherein, It also includes a temperature sensor, which is electrically connected to the analog signal input end of the single-chip microcomputer; the temperature sensor is installed on the circuit board.

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